The operator's compartment of most commercial vehicles, such as the cockpit of an airplane, generally includes at least one control panel. The control panel includes a plurality of high and/or low current switches that are in communication with a variety of electrical or hydraulic systems. Actuation of low current switches produces a relatively low current output to activate the switching action of a larger driver circuit. Such driver circuits are used to actuate a variety of systems, such as the landing gear or running lights of the vehicle.
High and low current switches currently available for such systems include both contact and contactless switches. Contact switches generally include a canister, a subminiature switch, an actuator and a tactile response mechanism. Located at one end of the canister is a cap assembly. Mounted at the other end is a terminal plate having a plurality of pins extending therethrough. Sub-miniature switches for such switches include a plunger reciprocally mounted to the subminiature switch. The plunger actuates the switch between an open circuit and closed circuit position in response to a linear movement. Such subminiature switches are mounted within the canister such that movement of the plunger is coaxial with the movement of the actuator.
Typical actuators used for contact switches include spring loaded force cap actuators that reciprocate within a sleeve disposed within the canister. The actuator is coupled to the movement of the cap assembly, such that the actuator translates in a direction that is parallel with the cap. As a result, displacement of the plunger must be aligned in a direction that is parallel to the displacement of the cap and actuator stroke.
Currently available contactless switches generally include a magnet and a sensor that is sensitive to magnetic forces to produce electronic control pulses. In a typical contactless switch, the magnets are permanently mounted to a device that is either rotated or linearly translated into close proximity with the sensors to change the state of the switch. In contactless switches having linear translations of magnets, the switch may also include a separate tactile mechanism coupled to the translation of the magnets to produce a tactile response while changing the state of the switch. A tactile response is desirable because it allows the operator to confirm actuation of a particular system without requiring visual confirmation. Although both contact and contactless switches are effective at changing the state of a switch, they are not without problems.
First, because the subminiature switches must be orientated within the canister such that its plunger stroke is parallel with the cap and actuator stroke, such switches have a rigid pin pattern definition. This is undesirable because it does not allow electric interface connections to be modified for an existing subsystem installation. Second, because the tactile response is typically a separate mechanism, such a switch is complex to assemble and maintain. Finally, for alternate action switches, hold down of the switch into either the opened or closed circuit positions is accomplished by a separate latching mechanism. Therefore, such a switch is also more complex and expensive to manufacture.
Thus, there exists a need for a switch that not only produces an anticipated tactile response, but is also economical to manufacture, has a high degree of reliability and satisfies the performance expectations of the end user.